My 2006 Hyundai Accent is revving when I put my foot on the brake

It’s very possible that this is a problem with the brake’s booster system. To give the braking system extra oomph, it uses a vacuum operated booster unit that multiplies the force in your leg. The vacuum comes from the engine’s intake system. If this booster develops a vacuum leak, it can allow excess air into the engine’s intake manifold. This extra air messes up the air-fuel mixture and the engine can start to rev up.

The brake booster is the first place a mechanic will check when presented with this problem.